Canning and Preserving

High Acid Foods vs. Low Acid Foods

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Canning and Preserving

It is important when home canning garden produce that you follow directions given in the recipes for safe handling when Preserving Foods.

The bacterium that causes food poisoning exists in the soil and is found on fresh foods, although not in dangerous quantities-not yet.

For the bacteria to grow it requires a vacuum and a non-acidic environment. It becomes potentially harmful only when food is improperly canned.

Choose your canning method carefully based on the acidity of the food. The more acidic the food, the safer it is to use the lower temperatures of the water bath canning method. Learn more about High Acid Foods

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High Acid Foods

High acid foods like fruits can be processed by the boiling water bath. Water Bath Canning is a process that submerges canned jars of high acid foods in boiling water, exposing the jars to high temperatures for a sustained period of time, never less that 10 minutes.

This action kills bacteria, molds, and yeast that would otherwise spoil the preserved food.

When processing high acid foods, jars are often packed densely so that all the food in the jar reaches the same temperature.

The boiling water bath also drives out any air in the jar to create a vacuum that causes the rubber coated canning lid to form a seal.

Only high acid foods such as Tomatoes can be canned using the boiling water bath method. Tomatoes are close to borderline PH and for this reason lemon juice is added to every jar of tomato based foods.

Other high acid foods that are suitable for canning in this way are berries, pickles, preserves, relishes, jams, chutneys, jellies, and butters.

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Low Acids Foods

Low acid foods require canning temperatures higher than that of boiling water to destroy bacteria. Since some foods lack in high acidity, bacteria is free to grow in the vacuum created in the jar.

Low acid Vegetables and meats are particularly susceptible to bacteria growth, but are perfectly safe if you process in a Pressure Canner and check for good seals afterward.

Using a pressure canner exposes low acid foods to high temperatures of 240 degrees to sterilize the food and destroy the microorganisms.

Low acid foods include all vegetables except for tomatoes. Seafoods, all meats and dairy products and mixtures like soups must be processed by the pressure canner method.

When pickling, keep in mind that only vegetable products that are pickled with a high vinegar content such as sauerkraut, pickles, and some Mustards do not require processing with a pressure canner.

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Canning and Preserving Tips

*Use the dishwasher on it's hottest setting to pre-wash jars for Canning and Preserving when using either the water bath or Pressure Canner methods. You can also sterilize jars in boiling water if you don't have a dishwasher prior to filling.

* To test acidity (pH), dip a strip of litmus paper into a sample of liquid. A reading below 4.0 is required to ensure proper acidity and canning safety.

Look for these signs of spoiled food before serving preserved foods, as always, when in doubt, throw it out.

* Mold on jar or food has leaked out during storage.

* The food is darkly or completely discolored. The food looks cloudy, slimy, shriveled, or spongy.

* The liquid in the jar seems to bubble and the food smells bad.

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Whether canning and preserving high acid foods or low acid foods, the most important step occurs before you even begin.

Preparation is key in each successful canning session. Before you start, line up your Canning Supplies and read through the recipe. Make certain that you have the necessary ingredients and utensils on hand.

Canning and preserving is an exact science and it is imperative to keep the time between harvesting and processing as short a possible to achieve success.

Being prepared beforehand ensures there will be fewer surprises, especially for a novice canner.

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